US 2003/0118641 A1 describes a procedure for reducing the abuse potential of oral pharmaceutical forms which contain extractable opioids. In this procedure, resistance to active compound extraction by means of customary domestic solvents, such as isopropyl alcohol, vodka, white wine vinegar, hot water or peroxides, 0.01 HCl in diluted alcohol, should in particular be brought about. It is proposed to formulate the active compound with a matrix-forming polymer and an ion exchange material, e.g. styrene-divinylbenzene polymers, in micronized form. The ion exchange material is crucial for the function of increased resistance to active compound extraction. The matrix-forming polymer obviously serves as a structure-imparting agent for the pharmaceutical core. A long list of possible substances is specified for the matrix-forming polymers, which among many other substances also comprises polymethacrylates. Preferred matrix-forming agents are C1-C6-hydroxyalkylcelluloses.
US 2004/0052731 A1 describes a pharmaceutical form, in particular suitable for opioid active compounds, which should contribute to the reduction of the abuse potential as a result of improper administration. It is proposed to combine a lipophilic active compound variant with a water-insoluble additive, such as, for example, a fatty acid or crosslinked water-soluble polysaccharides.
US 2005/0163856 A1 describes a therapeutic procedure for the treatment of patients suffering from pain with an oxycodone-containing pharmaceutical form having reduced abuse potential as a result of dissolution in a solvent and subsequent improper administration. To this end, the active compound should be formulated with a matrix-forming polymer selected from the group consisting of hydroxypropylcellulose, hydroxypropylmethylcellulose or hydroxyethylcellulose.
WO 2006/002884 A1 describes oral administration forms safeguarded against abuse, which contain a polymer, in particular a polyalkylene oxide, having a fracture resistance of at least 500 N.
WO 2006/094083 A1 describes a pharmaceutical form having controlled venlafaxine release characteristics. For the reduction of the abuse potential by addition of ethanol, the active compound is integrated into a matrix of a gelling, crosslinked polymer, e.g. xanthan. Further hydrophobic polymers, inter alia also polymethacrylates, can be added as additives.
WO 2006/125483 describes the use of a polymer mixture for the production of coated pharmaceutical formulations and pharmaceutical formulations with mixed polymer coatings. The polymer mixtures are intended to provide modified release profiles, tailor made for the certain therapeutically requirements of different pharmaceutical ingredients, which cannot be achieved by using standard polymers. There is no indication about ethanol resistant pharmaceutical forms. In the examples pharmaceutical forms coated with mixtures of Eudragit® NE and Eudragit® FS at ratios from 5 to 50% by weight of Eudragit® FS are described. However no talcum is used in the examples or recommended in the description at high amounts as used in the present invention. The suitable thickness of the coatings from 2-20% by weight, based on the weight of the core, is much lower than those thicknesses required for the present invention.
WO 1994/0022431 A1 describes an oral pharmaceutical preparation containing a therapeutically effective amount of morphine for administration. It consists of at least 50 individual particles with an individual particle size in the range of 0.7 to 1.4 mm. Each particle has a core containing a salt of morphine coated with a barrier layer. The barrier layer contains at least one water insoluble component selected from the group of ethyl cellulose, copolymers synthesized from acrylic or methacrylic esters and natural waxes, and a plastisizer, for providing drug release through the coating barrier layer which is substantially independent of pH in the range of 1.0 to 7.0. The resulting serum concentration of morphine obtained is at least 50% of the maximum serum concentration during at least 12 hours after the administration of a single dose of said preparation.
US 2007/053698 discloses methods of sustained release administration of opioids, including but not limited to hydromorphone and oxycodone, that exhibit improved properties with respect to co-ingestion with aqueous alcohol.